No. 893 is an 850˚F, electrically heated walk-in oven used for heat treating parts. Workspace dimensions measure 54 inches wide x 72 inches deep x 78 inches high. Eighty kilowatts are installed in Incoloy-sheathed tubular elements to heat the oven chamber, while a 6,000-CFM, 5-HP recirculating blower provides combination airflow to the workload. The oven has 8-inch-thick insulated walls comprised of 2 inches of 1900˚F block and 6 inches of 10 lb/cf density rockwool insulation. Controls on No. 893 include a digital programming and recording temperature controller, manual reset excess temperature controller with separate contactors, recirculating blower airflow safety switch, SCR power controller and fused disconnect switch.